Hello,
I built plasma cutting 4x8 feet. I used rack and pinion and stepper motor with pinion directly on motor shaft. approximate dia of pinion is 30 mm. My pulse per unit setting is 76. The cutting finish of job is very poor. If I hold torch with hand i can feel vibrations. I trie replacing rack an pinion with timing belt but the problem persist.

kindly point out various reasons from where I can reduce vibrations,

thanking you,
deepak